15.10 Global-to-local reconstruction

In a two-block dueling deep Q-network (DQN), the zero-inclusive global phase preserves return but reduces tangent obstruction by only \(3.92\% \), below the registered \(5\% \) gate. Critic-only local heads reconstruct only about \(54\% \) of the global obstruction variance. Adding the shared Bellman overlap \((y,D_sy\, v)\) raises reconstruction \(R^2\) to \(0.989/0.994\) and reduces normalized gluing error to \(0.0057\). Shuffling that overlap destroys the result.

Local/global repair-gradient cosines remain only \(0.464/0.584\). The study therefore supports localization of obstruction data, not yet compositional local repair.